Breeding And Field Performance Of Rice Varieties Derived From Transgenic Parental Lines Containing CryIA(b) And Xa21 Resistant Genes

In this study, we crossed two transgenic rice lines: Zhendao88 andShengdao301, which contain the cryIA(b) and Xa21 genes, respectively.We studied the genetic segregation pattern and stability of transgeneexpression in their hybrid progeny using selectable marker and reportergenes (bar gene and gus gene, respectively), PCR amplication andSouthern blot analyses.The results demonstrated that the bar and Xa21 genes co-inherited andco-expressed in hybrid progenies.Basta resistance assays and histochemical GUS staining showed a typicalMendel segregation ratio of 9:3:3:1 in the F2 generation, and stablehomozygotes of cryIA(b) and Xa21 in the F3 generation. PCR amplicationand Southern blot assays of F3generation and parental lines revealed thatthe cryIA(b) and Xa21 genes could be stably inherited.Using field breeding, we finally acquired three new transgenic lines withgood agronomic traits: SK-1, SK-2, and SK-3, which all showed obviousresistance to rice leaf folder (Cnaphalocrocis medinalis), striped stemborer (Chilo suppressalis) and rice bacterial blight (Xanthomonas oryzaepv. Oryzae). The yield potential for the hybrids of three new lines wasabout 13.20%, 18.19% and 14.83% higher than that of Zhendao88 and 2山 东 农 业 大 学 硕 士 学 位 论 文17.63%, 22.82% and 19.33% higher than that of Shengdao301. Moreover,the quality was similar and some features were better.